Tag: impact craters

We shall not cease from exploration, and the end of all our exploring will be to arrive where we started and know the place for the first time.– T. S. Eliot

It is important to know that the space age did not create the environmental movement.Much has been written about the affect of the “Earthrise” photo on the public consciousness in 1969 as the Earth Day movement got started.Certainly the experiences of the Apollo astronauts looking back at a small blue earth in the distance contributed to the general knowledge that the earth is small, fragile, and in need of protection.But the conservation movement anti-dates the space age by at more than a century.Think of John Muir and Teddy Roosevelt in this country among the many who have been concerned about our planet.

Having properly noted those facts, however, we should remember that space exploration profoundly affects how we understand our environment, the weather, the climate, pollution, and the weighted affects of human and natural causes to changes in the world around us, both for good and for ill.

Any serious discussion of climate change, for example, relies extensively on satellite observations from space.That much is clear to anyone who studies the topic.

However, an equally important affect is our understanding of how planetary atmospheres and climates work.There are many predictions that are being churned out by global climate computer models which we need to understand.

If all the doctors in history had one patient to study, they could scarely have a complete understanding of the vast complexity of medical science. Similarly, those whose study is limited to only one planet would have an incomplete and biased view of how the oceans, atmosphere, solar affects, and human interaction all weave their complex interplay.

Planetary scientists have studied – at close range – planets with atmospheres and oceans, and planets with atmospheres and no oceans, planets with frozen oceans and no atmospheres, the atmosphere and workings of the sun, and many other intriguing and valuable iphenomena that builds up an understanding which is at the heart of the computer models that are of so much interest in the climate discussions of today.

Predictions are only as good as the information and models that are used in making the predictions.Better information is needed and better models are needed as well.Space exploration informs both aspects.

How about a subtle story that you may not have heard?

Scientists have known for over two hundred years that large meteorites or asteroids have periodically struck the earth. The natural erosion forces at work on the earth’s surface – and underneath due to plate tectonics – have erased most of the craters.Detecting large impact features on planet earth is not simple.

When the Apollo astronauts returned rocks from the moon in the late sixties and early seventies, one new class of rock that was incontrovertibly associated with impact craters were the shocked breccias.From the study of rocks of another world, geologists learned much about the identification of the rocks associated with impacts.Several types of rock that were not well understood, but which were noted as “interesting” became readily identified as impact shocked samples.

In the late seventies, geologists studying core samples obtained by the Mexican petroleum company Pemex, identified rocks coming from offshore rigs near the Yucatan as impact shocked rocks, sharing many characteristics with the lunar breccias.Taken together with other subtle clues, the geologists mapped out a huge and previously unknown impact crater that they named Chicxulub.Something big happened there about 65 million years ago.Something that you should know about.Something that might make you think about the big things that sometimes affect life on earth in profound ways.

Something we didn’t understand until we studied the rocks from another world.